The present invention relates generally to combustible waste incineration systems and, in a preferred embodiment thereof, more particularly provides an improved system for incinerating municipal, commercial and/or industrial solid waste, or any other non-hazardous combustible waste, and responsively generating process steam and/or electricity.
In the past, various systems have been proposed for incinerating waste and utilizing the resulting combustion gases discharged from the incineration apparatus to form steam which is used to drive a steam turbine electrical generator and/or produce a source of process steam. Conventional waste-to-energy systems of this type have been characterized by a relatively low energy conversion efficiency compared, for example, to natural gas fired electrical generating plants. This rather low efficiency is attributable to the fact that a significant portion of the thermal energy released in the combustion of the waste is expended in heating the combustion air delivered to the incineration equipment and in drying and heating moisture contained in the waste.
Frequently the waste delivered to the incineration equipment is so wet that the incineration process requires that another fuel (e.g., natural gas) be burned, providing additional heat to sustain combustion of the waste and to maintain a temperature high enough to ensure complete combustion of the waste. Also, the products of combustion of some wastes are corrosive to alloy steels which are generally used to achieve high steam superheat temperatures.
It is accordingly an object of the present invention to provide an improved waste incineration and energy generating system in which above-mentioned and other limitations and disadvantages associated with conventional waste-to-energy systems are significantly reduced, and a variety of other operational improvements are provided.